This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Approximately 2% of the US population in chronically infected with hepatitis C virus (HCV). Chronic HCV infections result in significant liver disease including cirrhosis and liver cancer in approximately 20%of infected individuals. The current therapy of interferon and ribavirin does not result in viral clearance in the majority of cases. A better understanding of the replication of HCV at a molecular level as well as the factors that determine whether an infection will proceed to chronic infection or viral clearance are essential for the development of improved antiviral strategies. These studies are important for both vaccine and antiviral development. This is subcontract from the SOUTHEASTERN COOPERATIVE HEPATTIS C RESEARCH GROUP (0024). The goal was to test a molecular clone of HCV that replicates in tissue culture for replication in chimpanzees.